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Abstract:

A method of manufacturing an OLED display includes: forming an organic
light emitting element on a first substrate; forming, on the organic
light emitting element, a thin film encapsulation layer that seals the
organic light emitting element with the first substrate; providing a
second substrate; forming a flexible protection layer on the second
substrate; attaching the first substrate and the second substrate to each
other; and separating the second substrate from the flexible protection
layer.

Claims:

1. A method of manufacturing an organic light emitting diode (OLED)
display, the method comprising: forming an organic light emitting element
on a first substrate; forming, on the organic light emitting element, a
thin film encapsulation layer that seals the organic light emitting
element with the first substrate; providing a second substrate; forming a
flexible protection layer on the second substrate; attaching the first
substrate and the second substrate to each other; and separating the
second substrate from the flexible protection layer.

3. The method of manufacturing of claim 1, wherein forming the flexible
protection layer on the second substrate comprises forming a sacrificial
layer between the second substrate and the flexible protection layer, and
wherein separating the second substrate from the flexible protection
layer comprises removing the sacrificial layer.

4. The method of manufacturing of claim 1, further comprising forming the
first substrate on a mother board and separating the mother board from
the first substrate, wherein the first substrate comprises flexible
resin.

5. The method of manufacturing of claim 1, wherein the thin film
encapsulation layer comprises a single-layered inorganic layer.

7. The OLED display of claim 6, wherein the flexible protection layer has
a thickness in a range between about 1 um to about 100 um.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of Korean
Patent Application No. 10-2011-0052904 filed in the Korean Intellectual
Property Office on Jun. 1, 2011, the entire contents of which are
incorporated herein by reference.

BACKGROUND

[0002] 1. Field

[0003] The described technology relates generally to an organic light
emitting diode (OLED) display, and a manufacturing method of an OLED
display. More particularly, the described technology relates to an OLED
display including a thin film encapsulation layer as an encapsulation
member and a manufacturing method of an OLED display.

[0006] An organic light emitting diode (OLED) generally display has a
self-emitting characteristic and does not need a separate light source,
such that the thickness and weight thereof are decreased, compared to a
liquid crystal display. The organic light emitting diode (OLED) display
typically has high-grade characteristics such as low power consumption,
high luminance, high reaction speed, and the like.

[0007] In general, the OLED display includes a substrate, an organic light
emitting diode disposed on the substrate and displaying an image, and an
encapsulation member facing the substrate while interposing the organic
light emitting diode therebetween to encapsulate the organic light
emitting diode.

[0008] Recently, a flexible OLED display using a thin film encapsulation
layer as an encapsulation member has been developed.

[0009] However, a conventional flexible OLED display needs to attach a
flexible protection layer such as a polymer film to a thin film
encapsulation layer to protect the thin film encapsulation layer from
external interference. The protection layer cannot be easily attached to
the thin film encapsulation layer due to movement of the flexible
protection layer. Particularly, when the OLED display is large in size,
the flexible protection layer is also large-sized, and accordingly
attaching the protection layer to the thin film encapsulation layer
becomes more difficult.

[0010] The above information disclosed in this Background section is only
for enhancement of understanding of the background of the described
technology and therefore it may contain information that does not form
the prior art that is already known in this country to a person of
ordinary skill in the art.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

[0011] One embodiment provides a manufacturing method of an OLED display
that can easily handle a flexible protection layer.

[0012] Another embodiment provides an OLED display of which a flexible
protection layer is easily attached to a thin film encapsulation layer.

[0013] One aspect provides a manufacturing method of an OLED display,
including: forming an organic light emitting element on a first
substrate; forming, on the organic light emitting element, a thin film
encapsulation layer that seals the organic light emitting element with
the first substrate; providing a second substrate; forming a flexible
protection layer on the second substrate; attaching the first substrate
and the second substrate to each other; and separating the second
substrate from the flexible protection layer.

[0014] The flexible protection layer may include resin.

[0015] Forming the flexible protection layer on the second substrate may
include forming a sacrificial layer between the second substrate and the
flexible protection layer, and separating the second substrate from the
flexible protection layer may include removing the sacrificial layer.

[0016] The manufacturing method of the OLED display further includes
forming the first substrate on a mother board and separating the mother
board from the first substrate, and the first substrate may include
flexible resin.

[0017] The thin film encapsulation layer may include only a single-layered
inorganic layer.

[0018] A second aspect of the present invention provides an OLED display
manufactured by the manufacturing method of the OLED display.

[0019] The flexible protection layer may have a thickness in a range
between about 1 um to about 100 um.

[0020] According to one embodiment, a manufacturing method of an OLED
display that can easily handle a flexible protection layer is provided.

[0021] In addition, an OLED display of which a flexible protection layer
is easily attached to a thin film encapsulation layer is provided.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 is a flowchart of one embodiment of a manufacturing method
of an organic light emitting diode (OLED) display.

[0023]FIG. 2 to FIG. 6 illustrate an embodiment of the manufacturing
method of the OLED display.

[0024]FIG. 7 is a cross-sectional view of an embodiment of an OLED
display.

[0025]FIG. 8 is a layout view of a pixel structure of the embodiment of
an OLED display shown in FIG. 7.

[0026] FIG. 9 is a cross-sectional view of FIG. 8, taken along the line
IX-IX.

[0027]FIG. 10 is a flowchart of another embodiment of a manufacturing
method of an OLED display.

[0028]FIG. 11 and FIG. 12 illustrate another embodiment of the
manufacturing method of the OLED display.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

[0029] In the following detailed description, certain embodiments are
shown and described, simply by way of illustration. As those skilled in
the art would realize, the described embodiments may be modified in
various ways, without departing from the spirit or scope of the present
invention.

[0030] Accordingly, the drawings and description are to be regarded as
illustrative in nature and not restrictive. Like reference numerals
generally designate like elements throughout the specification

[0031] In addition, the size and thickness of each component shown in the
drawings are arbitrarily shown for understanding and ease of description,
but the present invention is not limited thereto.

[0032] In the drawings, the thickness of layers, films, panels, regions,
etc., may be exaggerated for clarity. In the drawings, for understanding
and ease of description, the thicknesses of some layers and areas may be
exaggerated. It will be understood that when an element such as a layer,
film, region, or substrate is referred to as being "on" another element,
it can be directly on the other element or intervening elements may also
be present.

[0033] In addition, unless explicitly described to the contrary, the word
"comprise" and variations such as "comprises" or "comprising", will be
understood to imply the inclusion of stated elements but not the
exclusion of any other elements. Further, throughout the specification,
"on" implies being positioned above or below a target element and does
not imply being necessarily positioned on the top on the basis of a
gravity direction.

[0034] Hereinafter, one embodiment of a manufacturing method of an organic
light emitting diode (OLED) display will be described with reference to
FIG. 1 to FIG. 6.

[0035] FIG. 1 is a flowchart of an embodiment of a manufacturing method of
an OLED display. FIG. 2 to FIG. 6 illustrate an embodiment of the
manufacturing method of the OLED display.

[0036] As shown in FIG. 1 and FIG. 2, an organic light emitting element
300 is formed on a first substrate 100 (S110).

[0037] A plurality of wire portions 200 arranged at a distance from each
other, and a plurality of organic light emitting elements 300 arranged at
a distance from each other are formed on the first substrate 100. The
first substrate 100 is made from a material including at least one of an
inorganic material such as glass, resin, or metal. The material may be
light-reflective, light-transmissive, light-absorptive, or
light-transflective. A first barrier layer BL 1, including at least one
of an organic layer and an inorganic layer, is disposed between the first
substrate 100 and the wire portions 200. Each wire portion 200 and each
organic light emitting element 300 will be described in further detail in
the description of another embodiment of an OLED display.

[0038] A thin film encapsulation layer 400 is formed on the organic light
emitting element 300 (S120).

[0039] The thin film encapsulation layer 400 is formed on the organic
light emitting element 300 to seal the plurality of organic light
emitting elements 300 together with the first substrate 100. The thin
film encapsulation layer 400 includes an inorganic layer. The inorganic
layer may be a single layer or a multi-layer including at least one of an
aluminum oxide such as silicon oxide (SiOx), silicon nitride (SiNx),
titanium oxide (TiOx), and alumina (Al2O3) and silicon
oxynitride (SiON).

[0040] In some embodiments, the thin film encapsulation layer 400 includes
a single-layered inorganic layer. In other embodiments, the thin film
encapsulation layer 400 may be formed by alternately layering at least
one organic layer and at least one inorganic layer. The organic layer may
be a single or multi layer including a resin such as polyethylene
terephthalate (PET), polyimide (PI), and polycarbonate (PC), or may be a
single or multi layer including engineering plastic including at least
one of glass fiber reinforced plastic (FRP), polyethyleneterephthalate
(PET), and polymethylmethacrylate (PMMA). The inorganic layer may be a
single or multi layer including at least one of aluminum oxide such as
silicon oxide (SiOx), silicon nitride (SiNx), titanium oxide (TiOx), and
alumina (Al2O3) and silicon oxynitride.

[0041] In some embodiments, the following process is performed after the
thin film encapsulation layer 400 is formed on the organic light emitting
element 300. In other embodiments, the following process may be performed
after the organic light emitting element 300 performed. In such
embodiments, forming of the thin film encapsulation layer 400 may be
omitted.

[0042] As shown in FIG. 3, a flexible protection layer 500 is formed on
the second substrate 20 (S130).

[0043] The second substrate 20 may be rigid and include at least one of an
inorganic material such as glass, resin, or metal. A sacrificial layer
30, a flexible protection layer 500, and a second barrier layer BL2
having at least one of an organic layer and an inorganic layer are
sequentially formed on the second substrate. The sacrificial layer 30 may
be an insulating layer including at least one of metal, an amorphous
material, silicon oxide, silicon nitride, and a metal oxide. The flexible
protection layer 500 includes a resin and has a thickness between about 1
um to about 100 um. In some embodiments, the flexible protection layer
500 may be a polymer film. Since the flexible protection layer 500 has
the above-stated thickness and flexible characteristic, it may be moved
due to external interference or stress, but the flexible protection layer
500 remains fixed by the second substrate 20 because it is formed on the
rigid second substrate 20.

[0044] As shown in FIG. 4, the first substrate 100 and the second
substrate 20 are sealed to each other (S140).

[0045] The first substrate 100 and the second substrate 20 are sealed to
each other such that the flexible protection layer 500 and the thin film
encapsulation layer 400 are arranged opposite to each other. The
attaching between the first substrate 100 and the second substrate 20 may
be performed by forming an adhesive layer on at least one of a surface of
the thin film encapsulation layer 400 and a surface of the second barrier
layer BL2.

[0046] The flexible protection layer 500 is attached on the thin film
encapsulation layer 400 together with the second substrate 20. The
flexible protection layer 500 is rigidly fixed to the second substrate
20. Accordingly, the flexible protection layer 500 can be easily attached
to the thin film encapsulation layer 400 without having a difficulty in
handling of the flexible protection layer 500 due to movement of the
flexible protection layer 50. Although the first substrate 100 is
large-sized, the flexible protection layer 500 that is large in size
corresponding to the first substrate 100 is attached to the thin film
encapsulation layer 400 in the state of being rigidly fixed by the second
substrate 20, and therefore the flexible protection layer 500 can be
easily attached to the thin film encapsulation layer 400. Further,
although the thickness of the flexible protection layer 500 is less than
about 1 um, the flexible protection layer 500 is attached to the thin
film encapsulation layer 400 while being rigidly fixed by the second
substrate 20 so that the flexible protection layer 500 can be easily
attached to the thin film encapsulation layer 400. The flexible
protection layer 500 is attached to the thin film encapsulation layer 400
by fixing the same to the second substrate 20 so that the flexible
protection layer 500 can be easily attached to the thin film
encapsulation layer 400 without considering movement of the flexible
protection layer 500. The flexible protection layer 500 may be an optical
film of a polarizing or phase difference film.

[0047] As shown in FIG. 5, the second substrate 20 is separated from the
flexible protection layer 500 (S150).

[0048] The second substrate 20 is separated from the flexible protection
layer 500 by removing the sacrificial layer 30 using a lift-off or
wet-etching process. The separated second substrate 20 may be recycled in
the next process.

[0049] As shown in FIG. 6, another embodiment of an OLED display (to be
described below) is manufactured by cutting the first substrate 100, the
first barrier layer BL1, the thin film encapsulation layer 400, the
second barrier layer BL2, and the flexible protection layer 500 along an
imaginary cutting line CL disposed between neighboring organic light
emitting elements 300 among the plurality of organic light emitting
elements 300 using a cutting means such as laser or a diamond cutter.

[0050] As described, according to an embodiment of the manufacturing
method of the OLED display, the flexible protection layer 500 is attached
to the thin film encapsulation layer 400 together with the second
substrate 20 while being rigidly fixed by the second substrate 20 so that
the flexible protection layer 500 can be easily attached to the thin film
encapsulation layer 400 without having a difficulty in handling of the
flexible protection layer 500 due to movement of the flexible protection
layer 500. As described, as the flexible protection layer 500 attached to
the thin film encapsulation layer 400 can be easily handled by using an
embodiment of the manufacturing method of the OLED display, an OLED
display large in size and slim in thickness can be easily manufactured by
setting the thickness of the flexible protection layer 500 to, for
example, about 1 um.

[0051] Hereinafter, another embodiment of an OLED display will be
described with reference to FIG. 7 to FIG. 9. Another embodiment of the
OLED display may be manufactured by the manufacturing method of the OLED
display according to the above-described embodiment.

[0052]FIG. 7 is a cross-sectional view of another embodiment of an OLED
display.

[0053] As shown in FIG. 7, an embodiment of the OLED display includes a
first substrate 100, a first barrier layer BL1, a wire portion 200, an
organic light emitting element 300, a thin film encapsulation layer 400,
a second barrier layer BL2, and a flexible protection layer 500.

[0054] The first substrate 100 may be flexible, making the entire OLED
display flexible. The thin film encapsulation layer 400 may be formed as
a thin film, and the flexible protection layer 500 may be slim.

[0055] The wire portion 200 includes first and second thin film
transistors 11 and 21 (shown in FIG. 8), and drives the organic light
emitting element 300 by transmitting a signal thereto. The organic light
emitting element 300 displays an image by emitting light according to the
signal transmitted from the wire portion 200.

[0057] Hereinafter, an internal structure of another embodiment of the
OLED display will be described with reference to FIG. 8 and FIG. 9.

[0058]FIG. 8 is a layout view of a pixel structure of an embodiment of
the OLED display. FIG. 9 is a cross-sectional view of FIG. 8, taken along
the line IX-IX.

[0059] The detailed structure of one embodiment of the wire portion 200
and the organic light emitting element 300 are shown in FIG. 8 and FIG.
9, but other embodiments are also possible. The structure of the wire
portion 200 and the organic light emitting element 300 may be variously
modified within a range that can be realized by a person skilled in the
art. For example, in the accompanying drawing, an active matrix (AM)
organic light emitting diode display having a 2Tr-1Cap structure that
includes two thin film transistors (TFTs) and one capacitor in one pixel
is shown as an OLED display. In other embodiments, the number of thin
film transistors, the number of capacitors, and the number of wires of
the OLED display may differ. The pixel represents a minimum unit
displaying an image, and the OLED displays an image using a plurality of
pixels.

[0060] As shown in FIG. 8 and FIG. 9, an embodiment of the OLED display
includes a switching thin film transistor 11, a driving thin film
transistor 21, a capacitor 80, and an organic light emitting element 300
which are formed in each pixel. The switching thin film transistor 11,
the thin film transistor 21, and the capacitor 80 are collectively
referred to as a wire portion 200. The wire portion 200 further includes
a gate line 151, a data line 171, and a common power line 172. The gate
lines 151 are arranged in one direction, and the common power lines 172
cross the gate lines 151 and the data lines 171 in an insulated manner.
In some embodiments, one pixel may be defined as the boundary of the gate
line 151, the data line 171, and the common power line 172.

[0061] The organic light emitting element 300 includes a first electrode
710, an organic emission layer 720 formed on the first electrode 710, and
a second electrode 730 formed on the organic emission layer 720. In some
embodiments, the first electrode 710 may be an anode, which is a hole
injection electrode, and the second electrode 730 may be a cathode, which
is an electron injection electrode. In other embodiments, the first
electrode 710 may be a cathode and the second electrode 730 may be an
anode. Holes and electrodes are injected into the organic emission layer
720 respectively from the anode 710 and the cathode 730. When an exciton,
in which a hole and an electron injected into the organic emission layer
720 are coupled to each other, falls from an excited state to a ground
state, light emission occurs. At least one of the first electrode 710 and
the second electrode 730 may have a light transmissive structure, and
accordingly, the organic light emitting element 300 displays an image by
emitting light to at least one direction of the first substrate 100 and
the flexible protection layer 500.

[0062] The capacitor 80 includes a pair of capacitor plates 158 and 178
arranged interposing an interlayer insulating layer 161 therebetween. The
interlayer insulating layer 161 may be a dielectric material, and
capacitance of the capacitor 80 is determined by charges charged in the
capacitor 80 and a voltage between the two capacitor plates 158 and 178

[0064] The switching thin film transistor 11 is used as a switch to select
a pixel for light emission. The switching gate electrode 152 is connected
to the gate line 151. The switching source electrode 173 is connected to
the data line 171. The switching drain electrode 174 is distanced from
the switching source electrode 173 and is connected with the capacitor
plate 158 of the two capacitor plates 158 and 178.

[0065] The driving thin film transistor 21 applies driving power to the
second electrode 730 for light emission of an organic emission layer 720
of an organic light emitting diode 300 of the selected pixel. The driving
gate electrode 155 is connected with the capacitor plate 158 that is
connected with the switching drain electrode 174. The driving source
electrode 176 and the other capacitor plate 178 are respectively
connected with the common power line 172. The driving drain electrode 177
is disposed at the same layer where the first electrode 710 is disposed,
and is connected with the first electrode 710.

[0066] In one embodiment of the OLED display, the driving drain electrode
177 and the first electrode 710 are disposed on the same layer, but a
driving drain electrode and a first electrode other embodiments of the
OLED display may be disposed in different layers and may access the first
electrode through an opening formed in an insulating layer.

[0067] With such a structure, the switching thin film transistor 11 is
driven by a gate voltage applied to the gate line 151 to transmit a data
voltage applied to the data line 171 to the driving thin film transistor
21. A voltage corresponding to a difference between a common voltage
applied to the driving thin film transistor 21 from the common power line
172 and the data voltage transmitted from the switching thin film
transistor 11 is stored in the capacitor 80, and a current corresponding
to the voltage stored in the capacitor 80 flows to the organic light
emitting element 300 through the driving thin film transistor 21 such
that the organic light emitting element 300 emits light.

[0068] Referring to FIG. 7, the thin film encapsulation layer 400 and the
flexible protection layer 500 are sequentially formed on the organic
light emitting element 300.

[0069] The flexible protection layer 500 has a thickness in a range
between about 1 um to about 100 um. In some embodiments, the flexible
protection layer 500 may have a thickness of about 10 um. The flexible
protection layer 500 is formed by embodiments of the manufacturing method
of the OLED display, and thus the flexible protection layer 500 is
disposed on the thin film encapsulation layer 400 by maintaining flatness
even though it has a thickness of about 10 um.

[0070] As described, an embodiment of the OLED display is manufactured by
using the embodiment of manufacturing method of the OLED display
described above so that it can be large-sized with a slim thickness.

[0071] Hereinafter, another embodiment of a manufacturing method of an
OLED display will be described with reference to FIG. 10 to FIG. 12.

[0072] Only characteristic portions that are different from the
embodiments above are described

[0073]FIG. 10 is a flowchart of an embodiment of a manufacturing method
of an OLED display. FIG. 11 and FIG. 12 illustrate an embodiment of the
manufacturing method of the OLED display.

[0074] As shown in FIG. 10 and FIG. 11, a first substrate 100 is formed on
a mother board 10 (S210).

[0075] The mother board 10 is rigid and includes at least one of an
inorganic material such as glass, resin, or metal. The first substrate
100 formed on the mother board 10 may be a polymer film, which is
flexible and includes resin. By being flexible, the first substrate 100
may be moved due to external interference or stress, but the first
substrate 100 maintains a fixed state because it is formed on the rigid
mother board 10.

[0076] An organic light emitting element 300 is formed on the first
substrate 100 (S220).

[0077] A wire portion 200 and an organic light emitting element 300 are
formed on the first substrate 100 including flexible resin.

[0078] A thin film encapsulation layer 400 is formed on the organic light
emitting element 300 (S230).

[0079] A flexible protection layer 500 is formed on the second substrate
20 (S240).

[0080] Next, the first substrate 100 and the second substrate 20 are
sealed to each other (S250).

[0081] As the first substrate 100 and the second substrate 20 are sealed
to each other, the flexible protection layer 500 and the thin film
encapsulation layer 400 are arranged opposite to each other. The
attaching between the first substrate 100 and the second substrate 20 may
be performed by forming an adhesive layer on at least one of a surface of
the thin film encapsulation layer 400 and a surface of a second barrier
layer BL2.

[0082] The flexible protection layer 500 is attached on the thin film
encapsulation layer 400 together with the second substrate 20 while the
first substrate 100 and the flexible protection layer 500 are being
respectively fixed to the rigid mother board 10 and the rigid second
substrate 20, and accordingly, the flexible protection layer 500 can be
easily attached to the thin film encapsulation layer 400 without having a
difficulty in handling of the flexible protection layer 500 due to
movement of each of the first substrate 100 and the flexible protection
layer 500.

[0083] As shown in FIG. 12, the second substrate 20 is separated from the
flexible protection layer 500 (S260).

[0084] Then, the mother board 10 is separated from the first substrate 100
(S270).

[0085] The mother board 10 and the second substrate 20 separated through
the above-stated process can be recycled in the next process.

[0086] An OLED display is manufactured by cutting the first substrate 100,
the first barrier layer BL1, the thin film encapsulation layer 400, the
second barrier layer BL2, and the flexible protection layer 500 along an
imaginary cutting line CL disposed between neighboring organic light
emitting elements 300 among the plurality of organic light emitting
elements 300 using a cutting means such as laser or a diamond cutter.

[0087] According to an embodiment of the manufacturing method of the OLED
display, the flexible protection layer 500 is attached on the thin film
encapsulation layer 400 together with the second substrate while the
first substrate 100 and the flexible protection layer 500 are being
respectively fixed to the rigid mother board 10 and the rigid second
substrate 20, and accordingly, the flexible protection layer 500 can be
easily attached to the thin film encapsulation layer 400 without having a
difficulty in handling of the flexible protection layer 500 due to
movement of each of the first substrate 100 and the flexible protection
layer 500. As the flexible protection layer 500 and the first substrate
100 attached to the thin film encapsulation layer 400 can be easily
handled by using embodiments of the manufacturing method of the OLED
display, an OLED display flexible, large in size, and slim in thickness
can be easily manufactured by setting the thickness of first substrate
100 and the thickness of the flexible protection layer 500 to, for
example, about 1 um to about 100 um.

[0088] While this disclosure has been described in connection with certain
embodiments, it is to be understood that the invention is not limited to
the disclosed embodiments, but, on the contrary, is intended to cover
various modifications and equivalent arrangements included within the
spirit and scope of the appended claims.